DRAINING LYMPH-NODE CELLS OF CONTACT-SENSITIZED MICE INDUCE SUPPRESSION OF CONTACT SENSITIVITY

The application of hapten to the skin of mice can induce contact sensi tivity (CS), It has also been well established that draining lymph nod e (DLN) cells can induce CS to the hapten used for skin painting when injected into naive mice, This is true for DLN cells recovered about 2 4 h after skin painting with hapten, It is unclear, however, whether D LN cells recovered shortly after hapten application have the same abil ity. By using an adoptive transfer assay system, we examined the abili ty of DLN cells recovered from mice at various times after skin painti ng with hapten to induce CS. DLN cells harvested 18-24 h after the app lication of fluorescein isothiocyanate (FITC) or 2,4-dinitrofluorobenz ene (DNFB) induced strong CS when injected into naive mice, DLN cells harvested 3-6 h after the application of FITC or DNFB induced either o nly weak or no CS but induced suppression of the subsequent immunizati on to the two haptens, The suppression was hapten-specific, MHC restri cted, and associated with the appearance of splenic suppressor T lymph ocytes, Analyses with antibodies and ultraviolet (UV) B radiation demo nstrated that suppression-inducing cells in DLNs were Ia(+), Thy-1(-), and functionally UV-sensitive. These data suggest that epicutaneous s ensitization with hapten first induces immunologically specific suppre ssor activity in the draining lymph nodes, whereas immunogenic activit y becomes predominant later.